Function getGeminiReasoning

src/api/transform/reasoning.ts:141–182

({
	model,
	reasoningBudget,
	reasoningEffort,
	settings,
}: GetModelReasoningOptions)

}

export const getGeminiReasoning = ({
	model,
	reasoningBudget,
	reasoningEffort,
	settings,
}: GetModelReasoningOptions): GeminiReasoningParams | undefined => {
	// Budget-based (2.5) models: use thinkingBudget, not thinkingLevel.
	if (shouldUseReasoningBudget({ model, settings })) {
		return { thinkingBudget: reasoningBudget!, includeThoughts: true }
	}

	// For effort-based Gemini models, rely directly on the selected effort value.
	// We intentionally ignore enableReasoningEffort here so that explicitly chosen
	// efforts in the UI (e.g. "High" for gemini-3-pro-preview) always translate
	// into a thinkingConfig, regardless of legacy boolean flags.
	const selectedEffort = (settings.reasoningEffort ?? model.reasoningEffort) as
		| ReasoningEffortExtended
		| "disable"
		| undefined

	// Respect "off" / unset semantics from the effort selector itself.
	if (!selectedEffort || selectedEffort === "disable") {
		return undefined
	}

	// Validate that the selected effort is supported by this specific model.
	// e.g. gemini-3-pro-preview only supports ["low", "high"] — sending
	// "medium" (carried over from a different model's settings) causes errors.
	const effortToUse =
		Array.isArray(model.supportsReasoningEffort) &&
		isGeminiThinkingLevel(selectedEffort) &&
		!model.supportsReasoningEffort.includes(selectedEffort)
			? model.reasoningEffort
			: selectedEffort

	// Effort-based models on Google GenAI support minimal/low/medium/high levels.
	if (!effortToUse || !isGeminiThinkingLevel(effortToUse)) {
		return undefined
	}

	return { thinkingLevel: effortToUse as unknown as GeminiReasoningParams["thinkingLevel"], includeThoughts: true }
}